Africa Day is celebrated on May 25 to commemorate the formation of the African Union. African citizens from all around the world celebrate with traditional clothes, songs and dances. Here, dancers perform during the Southern African Customs Union (SACU) Summit in Botswana in 2013. Photo: Flickr/GCIS

Citizens of African nations as well as ex-pat Africans based around the world are celebrating Africa Day on Monday to join under a common identity and mark progress on pressing issues. African students and leaders expressed cautious optimism about the future of the continent’s economic engine and social harmony.

Africa Day celebrates the anniversary of the formation of the African Union, which is an alliance between 54 member states to address shared issues and represent the continent in international negotiations. The Organization of African Unity was originally formed on May 25, 1963 and replaced by the African Union in 2001.

Residents of nations from South Africa to Egypt celebrated throughout the weekend by wearing traditional garments, playing music, dancing and posting to social media. South African President Jacob Zuma gave a speech on Sunday in Mamelodi, South Africa, to mark the occasion, and reminded Africans of the historical importance of banding together against common adversaries whether those be economic, social or military threats.

"That is part of celebrating and reclaiming the African identity of our country and people, which had been suppressed by the racist minority regime of the apartheid era," Zuma said.

The South African government's minister of sport and recreation took to Twitter to toast the occasion and celebrate.

The day is meant both to commemorate progress that has been made on social and economic issues across the continent, and as a time to consider the challenges that still remain, AllAfrica.com reports. In April, a rash of deadly attacks on foreigners swept through Johannesburg, South Africa’s capitol, amid concerns about unemployment. People from neighboring Zimbabwe make up the largest group of immigrants in South Africa, CNN reports.

Awaah Fred, who leads a group of students known as the All Africa Students Union based in Nigeria, told News 24 Nigeria that he was optimistic about the continent’s future even though Africa remains “engulfed in internal armed conflicts” as well as “civil and ethnic wars.” Africa’s economy grew by 4 percent in 2014, continuing one of the longest streaks of economic expansion in the continent’s history,according to the United Nations.

“[Africa’s] current positive economic growth, youthful and more and more well informed population and its immense natural resources make Africa the continent of the future if its institutions of learning are adapted to the reality, its structures of good governance and the management of its natural resources are upright,” he told the outlet.

I dream of #Africa tuned in to innovation and tech, leading the way; dataways, transborder highways, railway and super waterways #AfricaDay

The celebration set the stage for Zuma to urge all Africans to work more closely together on international as well as intracontinental issues. He asked all South Africans to learn the African Union anthem and fly the official AU flag alongside the nation's own flag, Eyewitness News reports.

This flag was designed by Yadesa Bojia and adopted as the official flag of the African Union in January 2010. Photo: Wikimedia Commons

"As South Africans, we are proud of our African identity,” he said. “We are proud to be part of a continent that is growing, that has a bright future."